Citric acid
C6H8O7 M.W: 192.1 M.P.: 153℃
Citric Acid should not contain C6H8O7 less than 99.5% and not more than 101% equivalent. Sitrik Asit, %99.5’tan az ve %101 ekivalanından çok C6H8O7 içermemelidir.
Properties: White, crystalline powder, colorless crystals or granules
Solubility: Very soluble in water, good soluble in alcohol, soluble in ether.
Recognition Reaction: 1 g is dissolved in 10 ml of water. Shows strong acid character against litmus paper.
Oxalic Acid: 1 g of compound is dissolved in a mixture of 1 ml of water and 1 ml of ethanol (95%)R; add 0.2 ml of calcium chloride TS, stand for 1 hour, the solution remains clear. Sulfate limit test: 0.5 g citric acid is dissolved in 5 ml water. Add 2 ml of diluted HCl and make up to 45 ml with water. Add 5 ml of BaSO4 reagent and allow to stand for 5 minutes. The resulting turbidity is not more than the standard turbidity.
Standard turbidity: Mix 25 ml of 0.01 N H2SO4 and 2 ml of dilute HCl R and make up to 45 ml with water. Add 5 ml of BaSO4 R and mix for 5 minutes.
Quantity Determination:
0.5 g is dissolved in 50 ml of water. It is titrated with 1 N NaOH.in the presence of 0.5 ml phenolphthalein.
1ml 1N NaOH ………. 64.03 mg citric acid
Reagents to be prepared:
CaCl2 TS: 10% w / v solution of calcium chloride hexanitrate in water.
Diluted HCl R: Take 26 ml HCl R and make up to 100 ml with distilled water.
BaSO4 reagent: Mix 15 ml 0.5 M BaCl2, 55 ml water and 20 ml ethanol R. Take 5 ml of K2SO4 from 0.0181% w / v solution in water and make up to 100 ml with water.
